simple?--from_meijer in jupyter

[Raymond Rogers]

The sympy documentation

http://docs.sympy.org/latest/modules/holonomic/convert.html

 has the function from_meiljer and I do 

from sympy import *

from sympy.holonomic.holonomic import from_hyper, from_meijer, DifferentialOperators

(I think redundant)

I get: "ImportError: cannot import name from_meijer"

Is this a versioning error or what?

As a side issue: I am trying to go from generalized hypergeometric <-> meijerg

Is there a better way than through holomorphic?

[Henri Girard]

from sympy.holonomic.holonomic import *

Have you tried this ?

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[Henri Girard]

Sorry if I spam :

I did this is it of any help as it works in sage-8.1

from sympy import *
from sympy.holonomic.holonomic import *
from sympy.holonomic import DifferentialOperators
from sympy.abc import x
from sympy import ZZ
R, D = DifferentialOperators(ZZ.old_poly_ring(x), 'D')
HolonomicFunction(D**2 + 1, x, 0, [0, 1])
HolonomicFunction((1) + (1)*D**2, x, 0, [0, 1])

Le 13/04/2018 à 00:06, Raymond Rogers a écrit :

[Raymond Rogers]

Yes I had that; I thought the whole thing was too redundant.

Here is a complete entry and response:

from sympy import *
from sympy.holonomic.holonomic import from_hyper, from_meijer, DifferentialOperators

from sympy.holonomic.holonomic import *
from sympy.integrals import laplace_transform
from sympy.abc import z, t,s,a
from sympy.holonomic.holonomic import *
  
x, y= symbols('x y   ')
k, m, n = symbols('k m n', integer=True)
f, g, h = symbols('f g h', cls=Function)
init_printing(use_unicode=True)
--
--Response

ImportError                               Traceback (most recent call last)
<ipython-input-139-0bf94d2c5de2> in <module>()
      1 from sympy import *
----> 2 from sympy.holonomic.holonomic import from_hyper, from_meijer, DifferentialOperators
      3 from sympy.holonomic.holonomic import *
      4 from sympy.integrals import laplace_transform
      5 from sympy.abc import z, t,s,a

ImportError: cannot import name from_meijer

--------------
And the suggestion in your following message works; or at least doesn't error out.
But the attempt to:
 
from sympy.holonomic import DifferentialOperators,  from_meijer, from_hyper

continues to fail irrespective of the ordering of from_meijer and from_hyper. 
I will check and see if that statement can be removed; perhaps it's not needed?

Ray

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[Eric Gourgoulhon]

Hi,

There is a typo in your code: it should be "from_meijerg" instead of "from_meijer":

sage: from sympy.holonomic.holonomic import from_meijerg
sage: from_meijerg?
Signature: from_meijerg(func, x0=0, evalf=False, initcond=True, domain=QQ)
Docstring:
 Converts a Meijer G-function to Holonomic. "func" is the G-Function
 and "x0" is the point at which initial conditions are required.

 >>> from sympy.holonomic.holonomic import from_meijerg, DifferentialOperators
 >>> from sympy import symbols, meijerg, S
 >>> x = symbols('x')
 >>> from_meijerg(meijerg(([], []), ([S(1)/2], [0]), x**2/4))
 HolonomicFunction((1) + (1)*Dx**2, x, 0, [0, 1/sqrt(pi)])
Init docstring: x.__init__(...) initializes x; see help(type(x)) for signature
File: ~/sage/8.1/local/lib/python2.7/site-packages/sympy/holonomic/holonomic.py
Type: function

Best wishes,

Eric.

[Raymond Rogers]

Sigh:   Yes...

Thanks!

Ray